Tire curing monitoring and control method

ABSTRACT

In the process of molding and curing pneumatic tires, a means senses certain selected quantities (e.g. cure cycle length) in the tire press and, in some applications, a post cure inflator, and feeds the sensed signals to a digital computer. The computer scans the input and compares it with pre-sorted ideal values. If the sensed data differs from the stored values by too great a degree, the computer provides an appropriate output. Further, the computer may control a tire marker to mark those tires which fail the comparison. In addition, by feeding information to the computer from a plurality of presses, accurate inventory counts, production requirements, production and press break-down history, and so forth, may be maintained automatically.

p 17, YE.J. NEUGROSCHL 3,836,614

TIRE CURING MONITORING AND CONTROL METHOD Original Filed Aug. 6, 1968 v 2 sheets-shee 1 FIGI E. J. NEUGROSCHL TIRE CURING MONITORING AND CONTROL METHOD Sept. 17, 1914 2 Sheets-Sheet 2 Original Filed Aug. 6, 1968 MARKER UNIT I .7 v w .J

INTERFACE DATA PROCESSING FIGS OUTPUT DEVICES w w w u M v 7 W ,7 fi a w m m 2 m 1 EB? @326 E i 8 E gm @3332 g I M I ullllllfqllllllf I I 7 ABSTRACT OF THE DISCLOSURE In the process of molding and-curing pneumatic tires, a. means senses certain selectedv quantities (e.g., cure cycle United States Patent 3,835,614 Patented Sept. 17, 1974 method for automatically monitoring and checking ,the operation of tire molding and curing apparatus.

It is another object of this invention to provide count of numbers of uncured tires fed into plant presses.

It is a further object of this invention to provide an inventory of tires molded and cured.

length) in the tire press and, in some applications, a post I cure .inflator, and-feeds the sensed signals to a digital computer. The computer scans the input and compares it with prestored ideal values. If the sensed data differs fromv the stored values by too .great a degree, the computer provides an appropriate output. Further, the computer may control a tire marker to .mark those tires which fail thecomparison. In addition, by feeding information to thecomputer from a plurality of presses, accurate inventory counts, production requirements, production and press break-down history, and so forth, may be maintained automatically.

This application is a division of my application Ser. No. 750,512 filed Aug. 6, 1968 and entitled Tire Curing Apparatus Monitoring and Control and U.S. Letters Patent 3,659,974.

This invention relates to a method for monitoring input,'opera'tion-' and output of pneumatic tire molding and curingapparatus.

' Modern tire plants contain a multitude of tire presses, eachpr'e'ss capable of molding and curing (vulcanizing) as many as'two tires every 15 to minutes. In view of the "increasing number of tire brands which must be pro duced-in 'a'large variety of tire sizes, the task of quality control, production scheduling, inventory control, maintenance, and so forth, have become most difficult. Further, the high "cost of'tire press equipment requires high utilization of such equipment to make most eflicient use of total press capacity.

Inolder' tire plants, counters, recorders and apparatus gauges are located at each tire press where they must bevisually monitored." Since supervision and collection of data from individual counters is cumbersome and ineflicient, a'prss malfunction or break-down is not detected immediately. The consequence is slowed production and inefficient use of total press capacity.

In newer plants, there has been a tendency to centralize counters and'some recorders or gauges of at least sections of presses or of some selected variables in central control-rOo'msJWhile this expediency speeds production monitoring, it still lags far behind the ideal.

In this invention, a' system is provided whereby sensors located at each press are connected at a central point to the'inpu't'of adata processing system. A digital computer repetitively scans the input terminals to monitor the operationof each press. Counts of uncured tires fed to" the presses are kept;'steps-in the molding and curing process are monitored for quality control by comparing the sensed parameters against pre-determined stored acceptableranges of values; cured tires maybe marked according to quality at the output of each press; and, accurate production reports-{machine malfunction reports, and so forth, are maintainedHAH outputs of this system are available immediately to supervisory personnel. 1t istherefore: .an object of this invention to provide a It is still another object of this invention to automatically compare ideal data against sensed data and provide exception messages when the comparison shows too great a departure from ideal values.

It is a still further object of this invention to mark times as they leave the presses with quality marks determined by the automatic comparisons.

It is a further object of this invention to provide a method which will make all the necessary production and quality control information available upon demand. 7

These and other objects of this invention will become readily apparent by reference to the following specification and drawings, wherein:

FIG. 1 is a generalized illustration of a tire press and post cure infiator;

FIG. 2 is a block-diagram of the system according to this invention, incorporating a single tire press and post cure inflator;

FIG. 3 is a schematic diagram of the interface circuit connecting each press with the input terminals of the data processing system.

This specification will set forth only information sufficient to understand the combination of the invention. It is not intended that this invention be limited to any single type or brand of tire press or post cure inflator. To the extent such devices differ slightly between manufacturers, a person skilled in this art could make the necessary modifications in this invention without departing from the scope thereof.

In the manufacturing of pneumatic tires, the components are assembled into uncured tires. Both bias ply uncured tires and radial ply uncured tires are placed automatically into the lower cavity of a tire press. As the upper cavity is lowered, an inflatable rubber bladder, or other means, is used to inflate the uncured tire, forcing it outwardly against the mold. When the upper cavity is completely lowered and the mold is closed, the bladder or other means presses the tire against the mold on all sides, and the tire takes on the tread design and markings carried by the mold.

Pressurized heated steam or other agent inflates the bladder or other means and heat is applied to the mold to cure the tire. In a typical passenger car tire, for example, steam at a first pressure of approximately psi. and then approximately 200 psi. and a temperature of approximately 300 F. is used to inflate the bladder. Curing time varies, depending upon the tire design and rubber compound, from 15 to 20 minutes in the case of the example tire above, to several hours in large earth mover tires.

As is Well known, many tire curing processes include; subsequent to the molding of the tire in the press, apo st cure inflation operation which comprises inflating the tire with air to a pressure which may be in the range of normal inflation pressure for the tire and permitting the tire to cool while so inflated. Generally the length of the post cure inflation cycle is twice the lengthof the cure cycle.

Use of the phrase tire molding and curing apparatus: in the specification and claims herein is intended to'en compass both a tire press alone and in combinatiori with apost cure infiator. r

It must be stressed that While ranges of time, temperature and pressure have been given, the value or each for any one tire is quite narrow. Each parameter is de' termined by the tire design and particular rubber corn pound used. Even slight variations from the prescribed parameters can result in a low grade tire. Further large variation may result in the necessity of the tire being scrapped.

Referring to FIG. 1, a generalized tire press 1 and post cure inflator 2 is illustrated. Uncured tires 3 are fed two at a time by automatic equipment (not shown) into lower cavities 4 of lower half 6 of the tire press. The uncured tires 3 are placed in the cavities around inflatable curing bladders 5.

After the uncured tires are positioned around the bladders in lower cavities 4, the upper half 7 of the tire press closes downwardly. As the press closes, steam lines 8, 9 deliver heated high pressure steam to the curing bladders, causing them to expand and mold the uncured tires against upper and lower cavities 10, 4 of the tire press. By regulation of steam pressure and temperature by means of a timing device (not shown), the proper heat is delivered to the curing tires.

After the prescribed curing time is completed, upper press half 7 raises, ejecting the hot tires onto delivery rollers 11, 12. If the tires are to undergo post cure inflation, they are mounted on the upper side of mandrels 14, 15 by automatic devices (not shown) and air inflated as described above.

The length of the curing cycle and the sequence and values of temperature and pressure are critical in the production of tires. Undercure results in insuflicient mo lecular cross-ties, producing a weak rubber. If the rubber is overcured, the rubber is excessively cross-tied, generally producing an inelastic, brittle rubber.

When post cure inflation is utilized, the time interval between ejection of the tire from press 1 and mounting and inflation on post cure inflator 2 is critical. Depending upon tire type and rubber compound, the time interval will fall in the range of 20 to 120 seconds.

At the same time a pair of tires is ejected from the press and mounted on post cure inflator 2, a further pair of uncured tires is automatically loaded into the press. Since press cure time is approximately one-half post cure time, the second pair of tires is ready for ejection half way through the post cure cycle of the first pair. As the second pair is ejected onto delivery rollers 11, 12, post cure inflator 2 is turned over, so that the second tire pair may be rimmed and inflated on the side of mandrels 14, 15 opposite the first pair. When a third tire pair is ejected from press 1, the post cure cycle of the first tire pair is completed and they are ejected as finished tires 17 and 18. The post cure inflator then turns over so that the third tire pair may be rimmed and inflated in the empty positions.

Parameters of the curing process are detected according to this invention by electrical sensors. Inflation of bladders is detected by pressure switches 21, 22 which are of conventional design. The pressure at which switches 21, 22 operate may be varied, but they must function at a pressure well below the minimum operating inflation pressure of the bladders. In the use of this invention, it has been found that 65 p.s.i. is a satisfactory operating pressure for the switches.

Opening and closing of the mold is sensed by contact switch 25. Turn-over of the post cure inflator is detected by contact switch 26.

The press is controlled by circuitry located in control cabinet 30. A typical controller consists of the well known timer cam in which a number of cams are mounted on an extended shaft which is turned at a constant rate. A cycle of the press and post cure inflator is controlled by one full turn of the timer shaft. Cams on the shaft contactswitches to operate the various press and inflator functions.

FIG. 2 illustrates the combination of this invention including a single tire press and post cure inflator. It should be understood that any number of presses and inflators may be connected into the combination of FIG.

2 in parallel with the single units illustrated. Further, a post cure inflator will not be used in all applications to which this invention is used. In those cases where no post cure inflator is utilized, marker 41 marks tires as they emerge from press 1.

Signals generated during the operation of press 1 and inflator 2 are fed to interface circuit 35. The interface converts the signals to a voltage and form acceptable by the input terminals of data processing unit 36. Unit 36 performs comparisons between sensed data .and stored data under control of acomputer program which will be discussed in detail below.

A detailed explanation of the operation of data processing unit 36 will be given below. For the present, it is suflicient to understand the forms the various output signals may take. If the unit determines that sensed data lies without allowable ranges, it generates signals which cause output device 40, which may take the form of a printer, to print an exception message. This message states the problem, such as overcure, and identifies the offending press cavity or post cure inflator stage. At'the same time as the exception message is generated, marker 41 may be controlled to appropriately mark the overcured tire. For marking purposes, color coded paint sprays may be used. The color of the spray is determined by the degree of variance from predetermined standards. Depending on the variance, the spray may indicate a second or third grade tire 'or a tire which must be scrapped. Alternatively, marker 41 could magnetically or otherwise encode grade designations on strips carried by the tires. In this fashion, the tire could be machine sorted.

Operation of the steam pressure switches 21, 22 (FIG. 1) indicates that uncured tires have been loaded. Operation of the post cure inflator turn-over switch 26 (FIG. 1), absent an intervening exception message, indicates the production of acceptable tires. All such signals are loaded into memory in data processing unit 36 and retained until they are read out. At appropriate times, this data is read out to device '40 and transferred to another digital storage medium such as discs. Once on the discs, the data is printed out in a format under the control of a program not part of this invention. These production reports may be made available tosupervisory personnel in a proper format whenever they are needed. As may be appreciated by anyone skilled in the art, output device may take whatever form is needed to produce a desired output.

Interface circuit 35 is shown in detail in FIG. 3. Lines 48 and 49 are control circuit power lines already present in the control cabinet. Initiation of a cure cycle is accomplished by closing contacts which turns on timer motor 47. During the time motor47 operates, which is the length of a cure cycle, voltage is applied to the primary side of transformer 51 by lines 52, 53.

Contacts 55, 56 are operated by pressure switches 21, 22 (FIG. 1). When, following the initiation of a cure cycle, steam pressure rises above a predetermined value in bladders 5 (FIG. 1), contacts 55, 56 close, applying voltage to the primary side of transformers 58, 59 over lines 61, 62 and 63, 64. I

Contact 67, operated by switch 25 (FIG. 1), is closed whenever the tire molds are closed. During the period when the molds are closed, voltage is applied across the primary of transformer over lines 71, 72.

In those applications where post cure inflation is used, contact is operated by the turn over switch 26 (FIG. 1) on the post cure inflator. As above, voltage is applied across the primary of transformer 77 over lines 79, 80 whenever the post cure inflator accepts or discharges a tire pair.

Transformers 51, 58, 59, 70 and 77 step downwhatever control circuit voltage is present to a level which may be connected to an intermediate interface or to the input terminals of the data processing unit, generally 24 volts. Since the data processing unit accepts only D.C. signals, full wave rectifiers 83, 84, 85, 86 and 87 convert the A.C. signal to DC. in well known fashion. The DC. voltages, representative of various curing process steps, are available between terminal plugs 90, 91, 92, 93 and 94 and the common line 96.

Data processing unit 36 must be capable of accepting data such as is generated by the sensing switches and interface 35. The unit utilized in this invention is the Model 1800 Data Acquisition and Control System manufactured by International Business Machines. Any equivalent system could be utilized with the appropriate program changes, where necessary.

In addition to the computer program, which is presented below, the data processing unit must be provided with the ranges of acceptable parameters for each tire type and rubber compound. These values are determined solely by the particular type and rubber involved and are not, therefore, set out here.

Parameters other than those set forth herein may be sensed and monitored. For example, temperature, in addition to pressure, of incoming steam may be monitored. Further, analog values of both temperature and pressure may be utilized rather than digital on-off" signals.

The program set forth below accepts sensed data and compares it with the pre-stored acceptable parameters, as described above. By sensing the length of time a signal appears on the secondary of transformer 51, the length of the cure cycle is monitored and compared to predetermined acceptable values. The length of time signals appear on the secondaries of transformers 58 and 59 yield the pressure-0n portion of the cure cycle, which is typically 5% shorter than the full cure cycle. In addition, signals from transformers 58 and 59 appear only when an uncured tire has been loaded into their corresponding tire cavity and may, therefore, be used also as production report data from each individual press cavity.

Opening of the tire mold is indicated by a signal on the secondary of transformer 70. Turn over of the post cure infiator is indicated by a signal on the secondary of transformer 77. Data processing unit 36 translates the relative time of occurrence of these two signals into a time interval signal which is critical in the tire curing process. Finally, the turn-over signal, when there are no intervening exception messages, is interpreted as indicating two completed tires to add to the finished production count. An intervening exception message, which signals a failure in the process, causes the finished production count to remain unaffected by the appropriate number of tires.

Data. manipulation by the data processing unit is under the control of the computer program. The program written in Fortran is set forth as follows. The instruction number is given immediately to the left of the Fortran instruction.

INTEGER SNAP(851) EXTERNAL LO G .ITEST(1170) EQUIVALENCE (MABO), ITRACO EQUIVALENCE (NUTS(1), NUT1(1 DIMENSION IZERO(112), IUNDR(112), [OVER(112), 1STAN(112), ISTAT(112) IDYNA(112), ITEST(112), 1SAVE(112), MAB(112),

ITRAC(112), NUTS(112), NUT1(66), NUT2(66) DIMENSION MESS(224), MESS1(123), MESS2(06), MESS3(5) COMMON/1NSKEL/[CNT(325), IPR(), MDTCT, ICHNG, ICHK, MSRCT, MWDAY, NLDCH QCISQPL)CH(7), NBLCH(7), NLDCL(7), MACNO,

IDATE(3), IPSW5, HUD, JOE, IPETE, KPETE, NOODA, LSTEM, IIIR(24), IJWK, UMO, IBOTH, ISTOP, IPRTI, KHO UR, IPWK(2) (NUTS(67), NUT2(1)) EQUIVALENCE (MESSO), MESS1(1)), (MESS(124), MESS2(1)), (MESSCIZO), MESS EQUIVALENCE (SNAP(1), ICNT(1)), (SNAP(326), IPR(1)). (SNAP(386), MDTCT), (SNAP(387), ICHNG), (SNAP(388), ICHK), (SNAP(389), MSRCT), (SNAP(3'.)0), MW DAY), (SNAP(301), NLDCH(1)), (SNAPGQB), NPLClItD), (SNAP(405), NBLCHO) (SNAP(412), NLDCL(1)), (SNAP(419), MACNO), NAP (810), 1DATE(1)), (SNAP(813), IPSW5, (SNAP(814,) MUD), (SNAP(815), JOE), (SNAP(816), IPETE), (SNAI(817), KPETE), (SNAP(818), NOODA) EQ UIVALENCE (SNAP(819), LSTEM), (SNAP(820), 1113(1)), (SNAP(844), UWK), (SNAP(845), UMP). (SNAP(816), IBOTH). (SNAP(847), ISTOP), (SNAP(8-18), 1P RT'I"), (SNAP(849), K110 UR), (SNAP(850), IPWK(1)) 11 DATA NMACH, lPROl, ISTPP, MSTAT/112, 40, 390, 13/

(SNAP(420), 1SCS(1)), (S

DATA N UTII 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21 ,22

whit- ,23,2-l,25.26,27,2B,Z),30,31,32,33,34.35,36,37,3S,39,40,41,42,43,44 ,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66

/ DATA NUT2/67, 68, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105

21, s2, s3. s4. s5, 86, 37, as, 89, 90/

15 DATA MESS1/1,2, 3,

101, 118, 117, 120, 119, 122, 121, 124/ DATA MESS2/123, 126, 125, 128, 127, 130, 129, 132,

DATA MESS3/220, 221, 222, 223, 224/ DATA ITIMA, ITIMB, ITIMC 4, 12,

DEFINE FILE 112(3, 320, U, NSRS) DEFINE FILE 1S(5,224,U,LTD) DEFINE FILE 49(l0,160.U,MXI) DEFINE FILE 499(10,160,U,M1X) READGHSTAT'UITRAC JTST1=JTSTS1 27 ICT =1 DO 20 IG=1,ISTPP,NWORD CALL BITMN(ISCS(IG+1) CALL BITMN DATA IBOTII, ILEFT. IRIGH/14, 12, 16/ DATA ISFT3, ISFTI, ISFTl, ISFT2, ISFT2, ISFT3/7000, 7040,15000, 15040, 230

DATA NWIRE, NWORD, NCALL, .ITSTS, KSTPP/4, 3, 0, 1170,13

CALL BITMNQISCSQ G),4.0,JTEST(ICT),12) CALL B1TMN(1SCS(1G),4,4,.ITESTUCT CALL BITMAN(ISCS(IG),4.8.JTEST(ICT+20),1 CALL BITMN(ISCS(IG),4,12,.ITEST(ICT+30),1'

,4,0,JTEST(ICT+4( ),1'.2) CALL BI'IMNHSCSUG+1),4.4,JTEST(ICT+50),12) CALL BITMNUSCSU G+1).4,8,JTEST(IC'I+60),12)

(ISCSUG+1),4.12,1TEST(ICT+70),12) CALL BlTMNtlSCSUG+2),4,0,JTEST(1CT+80),12)

TABLE-Continued TABLECont1nued 151 oo'ro 12130.v p 152 1123 WRITE(5.1166)MACHLMACHR DIMENSlON IMARK(NMACH) IMARK(NMACH)=81 Y CALL 11101,IMARmnJMA-Rmmmcn 153 Go To 1260 154 1200-1F(1TEST(N)1) 1205,1205,121o s E05t1SAVE(N)=0 159 1215 IF(N68) 1221,1221,1216 160 1216 IF(N112) 1Z22;122,130 161 1220 IF(ISAVE(N)9) 1260,1225,1170 162 1221 IF(ISAVE(N)S) 1260,1225,1170 163 1222 IF(1SAVE(N)-11)1260,1225,1170 164 1225 JB =MAB (N) 165 GO TO(1232,1230,1231,41),JB 166 1230 WRITE(5,207) MACHL 167 GO TO 1300 168 1231 WRITE-(5,207) MACBR '1 170 1232 WRITE(5,207) MACHL,MACHR GO TO 1300 172 99 WRITE(5,1267) N 173 GO 0 1260 174 163 .TB=MAB(N) 175 GO TO (165 300,31 13 176 165 lCNT(MACHL)=ICNT(MACHL)+1 177 310 ICN'1(MACHR)=ICNT(MACHR)+1 178 168 IS'IAN (N) =ISTAN (N) 1 179 IF(1STAN(N)-ISTAT(N))170,170,160 1.10 169 IUNDR(N)=IUNDR(N)+1 181 170 ISTAT(N) =0 19-1 211 1F(IPSW-ISF'I1)216,216,212 105 212 IF(IPSW-LSF'I1)218,216.213 190 213 IF(IPSW-ISFT2)216,216,214 197 214 IF (IPSW-LSFT2)2I8,216,215 198 216 IF(IPSW-1SF'13)216,216,218 199 216 IF (IPWK(2))175,217,175

200 217 CALL EONS 201 IPWK(2) =1 202 GO TO 175 203 218 IPWK(2) =0 20* 175 CALL DATSW(3,IT)

205 IF(IT1)177, 176, 177 206 176 WRITE(3,500)1PSW 207 WRITE (3,200) ICNT 208 177 IF(ISTOP1) 1777,1778,1777 209 1777 WRITE(112'1) SNAP 210 1778 CALL CLOCK (IPSW5) 211 I-IPSW5/10001000 212 I REM =IPSW5-J 213 IF (I REM-483) 179,1780,l779

214 1779 IF (I REM-517) 1780,1780,179 215 1780 CALL QUEUE (LO (123,1) 216 179 IF(IS'1OP2) 181,180,181

217 CALL LEVEL(7) 21S ISTOP=3 219 181 CALL IN'IEX 220 200 FORMAT(BAGOMATIC PRODUC'IION',//,11(2015,//),415,//,TIRE WATCH- 1 CASE',2(l/,l915) GREEN TIRE PRODUCTION/MACHINE,2(/l,2813)) 221 201 FORMATOH CAVITY,2X,14,2X,NOT CURINGI) 222 203 FOBMATOH CAVT.,2X,214,2X,DOWN-SET BY OPERATOR'J) 223 204 FORMAT(4(6X,13)) 224 205 FORMATC CAVITIE UNDER AND OVER-CURES/SHIFT') 225 206 FORMAT( CAVT. ',I3) 226 207 FORMATOH EXCESSIVE TIME BETWN CURES ON CAVIT,2X,I4,2X,14,/) 227 208 F0 RMA'1(2X,I2) 228 209 F%1I?5MAT( IF MACHINE NO.,2X,14,2X,IS NOW AVAILABLE-RESET MAB C 1 229 500 FORMA 230 FORMAT( OVERCURE CONDITION ON CAVI'I",2X,I4 2X,I4,/)

1166 231 1267 F0 RMAT( 232 210 END ILLEGAL BIT CONFIGURATION ON MACH,2X,14/)

As will be readily apparent to those skilled in the art, numerous modifications may be made in the disclosure herein without departing from the scope of this invention. Changes may be made in the manner in which process parameters are sensed and in the identity of the particular parameters without leaving the scope of this invention. While this invention has been described in combination with a steam bladder press, it is intended that the invention incorporate other types of presses, such as bladderless presses and bladder presses operated by hot water or air. Finally, as is realized by anyone skilled in the art, modifications in the computer program set forth herein may be made without changing the purpose or result of the program. It is intended that the invention be limited only by the following claim.

What is claimed is:

1. A method of monitoring a plurality of independent tire molding and curing apparatuses used for the manufacture of tires employing a central data processor comprising the steps of:

sensing the times of occurrence of discrete predetermined process conditions during the molding and curing cycles of tires in said apparatuses, generating signals at each of said times of occurrence for each of said apparatuses so that a set of signals is generated for each of said apparatuses,

periodically scanning said sets of signals associated with said plurality of apparatuses,

converting said sets of signals into second sets of signals corresponding to selected time intervals of critical importance in the tire molding and curing cycles,

comparing said second sets of signals with stored refer ence data which corresponds to predetermined allowable time intervals for each tire being manufactured including the acceptable time intervals for each tire type and rubber compound used in the manufacture of said tire types,

generating an output signal for each tire produced by each of said plurality of apparatuses dependent upon said comparisons and making a permanent record of said output signals dependent on ,said comparisons for each tire produced by said plurality of apparatus, respectively.

References Cited UNITED STATES PATENTS Canfield 264-40 X JAN H. SILBAUGH, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,836,6l DATED September 17, 197% INVENTOR(S) Ernst J. Neugroschl it ie certified that error appears in the above-identified patent and that said Letters Patent are'hereby corrected as shown below:

Column 2, line 12, "times" should read'-- tires In the computer program, beginning under Columns 5 and 6',

line l8, "16" should read l0 line 19, "DATA ISFT3, ISFTl, ISFTl, ISFT2, ISFT2, ISFT3" should read DATA LSFT3, ISFTl, LSFTl, ISFT2, LSFT2, ISFT3 line 30, ZJIESTUCTQO) ,12)" should read JTEST(ICT+10) In the computer program, under Columns 7 and 8,

line +l, ICT=ICT-J'TS'l'I" should read ICT=ICT-JTST1 line 80, "IF(PBT7/.2-IPBT/2)" should read IF(PRT'7/.2-IPRT7/2) line 85, "160, 111, 166" should read 160, 111, 160

In the computer program, under Columns 9 and 10,

line 185, "(IPRT7=IPRO1)" should read (IPRT'Z-IPROI) line 186, "IPRT -O" should read IPRT7=O line 211, "J-IPSW?" should read J=IPSW5 line 220, "//,11(2o15,//) 415,, TIRE WATCH- 1 CASE ,2(//,19155" should read 1cAsE',2(//,1915) line 228, "-RESET MAB C 1 ODE. should read --RESET MAB C lODE. 1/)

Signed and Sealed this I seventh Day of 0mm 1975 [SEAL] AIleSf. r

RUTH C. MASON C.. MARSHALL DANN' Arresting Officer Commissioner of Parents and Trademarks 

